Well-drilling tool



Nov. l5, 1949 T. A. cRElGHToN 2,483,003

WELL DRILLING TOOL Filed March 21, 1945 4@ .-F w 45 47 INVENToR. 43.ZOMAS. TGF/@Hmm BW MM A Trae/Vey.

:on the line 3--3 of Fig.. 2.

Patented Nov. 15,` 1949 WELL-DRILLING TOUL Thomas A. Creighton, LongBeach, Calif., assgnor of .one-third to Martha H. Wright, Los Angeles,

Calif.

Application March `21, 1945, Serial'No. 583,929

(Cl. .Z55- 72) 8 Claims.

This invention relates to lwell drilling tools and deals moreparticularly with well bits for use in the rotary method of drilling.The present-invention is an .improvement in the general type of bitwhich is the subject of Patent No. 2,1'l9y0l0, issued November '7.,1939.

As set forth in the aboveidentied-prior patent, during a well drillingoperation, it sometimes becomes necessary to perform a survey of thewell to test the earth formations being drilled, to determine thedirection of the hole being drilled, or to gather other information. Inthe said prior patent the means or core cutter provided `for 'breakingup the earth formation wor `core at the central portion of the vwellbore is subject to being deflected from the core cutting position byinstruments used during surveying'operations and is such as toautomatically return to cutting position upon withdrawal of Asuchinstruments from the bit. s

A working core cutter of the. character `mentioned is necessarily smalland during .use is subjected to forces tending to create great wear andoften such `as to cause fracture or failure thereof. Need for replacingthe core cutter frequently arises before it is .necessaryto replaceother-parts of the bit. With the structure of thersaid prior patent suchreplacement is generally diiiicult and time consuming and can beaccomplished properly only with shop facilities. Y It is an object ofthe present invention to provide a structure vthat facilitates fieldreplacement of a .core cutter of the general type present in the saidprior patent and in other similarl structures. Tt is another object ofthe invention Yto provide a well bitY in which a core cutting `means`with a hinged core cutter is releasably secured in a counterbore at thelower end `of the central ypassage provided through the body of the bit.Threaded engagement is Apreferably provided Vbetween Lthe core cuttingmeans and the body of the bit.

VThe lvarious objects and features of my invention will be fullyunderstood from the following -detailed description of typical preferredforms and applications of my invention, throughout which-'descriptionreference is made to the accompanying drawings, in which:

Fig. 1 is a side elevational viewof a rotary well drilling bitembodyingone kform-of the invention.

Fig. 2 is an .enlarged 'fragmentary longitudinal :sectional view takenas indicated by line 2-2 .of Fig. .1.

Fig. :3 isa .broken detail `sectional view as taken Fig. 4 is afragmentary bottom plan view as seen in the direction of the arrow 4 ofFig. 2.

Fig. 5 is a view similar to Fig. 2 of another form of drill bitembodying the invention.

Figs. 6 andv 7 are fragmentary cross sectional views taken on the lines6-6 and 1 1, respectively, of Fig. 5.

Fig. 8 is a broken detail sectional view as taken on the line 8 8 ofFig. 5.

The present invention may be embodied in well drilling bits of varioustypes and constructions. The following detailed description is based onvtypical forms of the invention embodied in drag type rotary bits andtherefore it is to be understood that the invention is not to beconstrued as limited or restricted to the specific details that may beshown or which may be described.

The bit construction shown in Figs. 1 to 4, inclusive, provides a bitbody I0 having a central vertical opening or bore II extending throughit from one end to the other for receiving or passing a surveyinginstrument A, cutting means I2 on the body I0 for cutting the well boreto gauge, and core cutting means I3 for cutting or breaking away thecentral earth formation or core left standing by the cutting means I2.

The body In of the bit is preferably in the form of a stem or shank.Typical means, such as a threaded socket -I 5, may be provided tofacilitate connection of the bit with a well drilling string. The bore II is preferably a central through bore or opening and may be reduced insize at the lower end portion of the bit as shown at Ila. This boreserves both to conduct circulation fluid vduring drilling and to passthe surveying instrument A. Means may be provided to assist in locatingand supporting the surveying instrument A and may comprise an annularflange I6 on the wall of the bore I I, spaced below the socket I5. Thereduced bore IIb formed by the ange together with the reduced boreportion IIal may serve to center and Alocate the surveying instrument Ain the bit body I0 or to guide a portion of f the instrument relative tothe bit.

The cutting means I2 may comprise cutting blades Il on the lower endportion of the body and may include cutting blades I8 on the upper endportion of the body Ill. The blades I1 may be termed leading or pilotblades and may act to form .an annular out in the earth formations toreceive, with suitable clearance, the bit body It. The blades I8 mayserve as reaming or bore yenlarging cutters acting to enlarge the wellhole formed -by thev :blades all .so vthat .the hole is. of

the desired size and so there is ample clearance for return flow ofcirculating iiuid.

The core cutting means I3 is provided to remove, cut, or break away theinner or central earth formations of the Well unaffected by the cuttersI'I and I8, and, as contemplated, is a unit threaded to the bit body andis provided with a cutter that is retractable or dislodgeable from itscutting position to permit the surveying instrument A to be arranged inor passed through the body bore II to make a well survey.

The core cutting means I3 may comprise one or more retractable cuttersor cutting dogs I9. One such cutter is shown in the drawing. Accordingto the invention, means are provided whereby the core cutting means I3may be easily and quickly removed from the bodyof the bit forreplacement and/or repair.

One manner of applying the means I3 to the bit includes an insert ormember such as a ring 20 disposed in a seat 2l or seat opening formed inthe body I from its lower end, and having threaded engagement with thebody as at 22. Threads on the exterior of the ring member enjgagethreads on the wall of the seat opening in the body that receives thering member. The axial bore 23 of the ring member forms an eX- tensionor continuation of the bore portion ila in the body II). The seat orseat opening 2l may be of such size as to leave the Wall portion 24 ofthe body surrounding the ring suiiciently strong to effectively supportthe means I3 and at the same time allow the ring 20 to be thick enoughto accommodate and effectively hold a pivot pin 2-5 for supporting thecutter I9. The inner end of the cutter i9 may be disposed in a notch orseat 26 formed in the ring 2B. The cutter is preferably provided withmeans normally yieldingly holding it in operation position where itextends to the center of the opening in the ring member 20. One suchmeans is preferably a yielding means and may comprise a torsion spring 2around the pivot pin 25 and having its ends in engagement with the ringat 28 and the dog at 23. Spring 2l' returns the cutter to workingposition after it has been depressed or deflected by passage of anobject or instrument through the means I3. The cutter YI9 is preferablyprovided with a blade or cutting edge portion 30, so arranged withrespect to the blades I'I as to completely break or cut away the coreleft by said blades II.

It will be recognized that the cutter I9 is necessarily limited in sizeand that the necessary details of its design are such that it is`subject to wear and possibly injury before the other parts of the bitare Worn or need replacement.

Should replacement of the cutter I9 become necessary, quick removal ofthe Worm or broken means I3, and replacement with similar means in goodrepair, may be accomplished by merely unthreading the means I3 from itsseat 2I and threading another like element into its place. Drillingoperations may then proceed. In this manner the bit I is given longerlife and much time is saved with resultant economic savings.

In other respects the bit of the instant invention functions similarlyto those disclosed in the above mentioned patent.

In the form of the invention shown in Figs. to 8, inclusive, the bit maycomprise a body 40 having a longitudinal bore 4I, cutting means 42, andone or more retractable cutting means 43. The body 40 may be providedwith a threaded socket 44 for connection with a drilling string and thecutting means 42 may follow generally the design of the blades I'I.

In this form of the invention a cutter 45 may be carried by a bar 46arranged, preferably, in a longitudinal slot 41 in the body 40. In thismanner the means 43 may be assembled into the bit from the top endthereof and held in place against shoulders or stops 48 on the body bythe pin, on a part of a drill string, engaged in the socket 44. Asbefore described, the cutter '45 may be pivoted to the bar as on a pin49 and spring means 5B may be provided to normally yieldingly hold thecutter in scraping or cutting position. The above provisions suitablylocate the means 43 longitudinally in the body of the bit. To hold thebar against inward displacement the slot 4l may be a dove-tail slot, asshown best in Fig. 7, and the bar 46 similarly shaped to fit the slot.The front or inner wall 5I of said bar may be made'concave to completethe bore 4I. In other vital respects this form of the invention mayfollow the form shown in Figs. 1 to 4. Replacement of the means 43 maybe made easily and with little loss of time.

It will be apparent that the cutting components of the bit will functionto eiectively bore a hole and that the center of said hole is removed orbroken during drilling by the core cutting means provided in the bit.When a surveying instrument is operated in or through the bit the corecutter may be readily dislodged or moved to a retracted position by theinstrument A and upon withdrawal of the instrument A the core cutterwill resume a normal core cutting position.

Having described only typical preferred forms and applications of myinvention, I do not wish to be limited or restricted to the specificdetails herein set forth, but wish to reserve to myself any variationsor modications that may appear to those skilled in the art and fallwithin the scope of the following claims.

Having described my invention, I claim:

1. A well drilling bit including a body having a longitudinal bore,cutting means on the body operable to make an annular cut in the earthformation leaving a central core of earth formation, core breaking meanson the body including a cutter operable to cut away said core andretractable by an object passed through the opening, and meansreleasably connecting said body and said core breaking means including,a longitudinal seat in said body and a member pivotally supporting thecutter of said core breaking means and carried by said seat, the seatbeing a longitudinal channel in the body and said member being anelongate bar retained in the channel.

2. A well drilling bit including an elongate body having a centrallongitudinal passage therethrough and a counterbore at the lower end ofthe passage entering the body from its lower end, cutting means on thelower portion of the body operable tc make an annular cut, membermounted in the counterbore and having an opening therethroughregistering with and corresponding in size to the said passage of thebody, a core cutter pivotally carried by said member, and means normallyyieldingly holding the core cutter in position to act on material leftby the said cutting means.

3. A well drilling bit including an elongate body having a centrallongitudinal passage therethrough and a threaded counterbore 'at thelower end of the passage entering the body from 'its lower end, cuttingmeans on the lower portion of the body operable to make a cut, anannular ma In 4. A well drilling bit including a body havingA alongitudinal bore, cutting means on the body operable to make an annularcut in the earth formation leaving a central core of earth formation,core breaking means, and means releasably connecting said body and saidcore breaking means including, threads on the body and mating ,threadson said core breaking means, the core breaking means including a pivotedcutter operable to cut away said core and retractable by an objectpassed through the opening.

5. A Well drilling bit including a body having a longitudinal bore,cutting means on the body operable to make an annular cut in the earthformation leaving a central core of earth formation, core breaking meansincluding, a cutter, a member engageable with the body and meanspivotally connecting the cutter and said member so the cutter isoperable to cut away said core and is retractable by an object passedthrough the opening, and means releasably connecting said body and saidcore breaking means including a longitudinal seat in said body carryingsaid member.

6. A well drilling rbit including a body having a longitudinal boreadapted to receive an object passed downwardly through the bit, cuttingmeans on the body acting to make an annular cut around a core, corecutting means including a member engageable with the body, a cutter,means connecting the cutter to said member to move relative theretobetween a core cutting position and a retracted position, and resilientmeans normally holding the cutter in the rst mentioned position, andmeans releasably connecting said core cutting means and said bodyincluding, threads on the body and mating threads on the core cuttingmeans, the cutter of the core cutting means being operable to theretracted position by an object passed through the bit.

'7. A well drilling bit including a body having a longitudinal boreadapted to receive an object passed downwardly through the bit, cuttingmeans on the body for making an annular cut around a core, core breakingmeans for normally acting to remove the core and retractable to aninoperative position by the mentioned object, said latter meansincluding, a cutter, a member engageable with the body, means mountingthe cutter on said member to move between a core fcutting and aretracted position, and means yieldingly holding the cutter in the corecutting position, and means releasably connecting said core breakingmeans and body, said latter means including a longitudinally disposedthreaded seat located centrally in said body and a thread on the saidmember of the core breaking means having engagement with the seat.

8. In a bit of the character described having a cutter supporting bodywith a central opening therethrough, core breaking means comprising anannular member carried in the body, the opening through said memberbeing in register with and the same size as the opening of the fbody,Vand a resiliently mounted cutter carried by said member, and means onsaid member releasably engaged with the bit including threads on theexterior of said member and cooperatively engaging threads on the body.

'THOMAS A. CREIGHTON.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,351,003 Pace Aug. 24, 19202,170,716 Higgins, Jr. Aug. 22, 1939 2,179,010 Creighton Nov. 7, 1939

